Never ending loop

I'm writing an infix to postfix program. All has been slowly but surely going well, but now I'm actually running the program after getting rid of all warning and errors the compiler found, and there's a problem with a loop somewhere that I can't figure out.

I'm pretty sure the problem lies in my queue class, as what I'm getting is endless lines of "Queue is full". But I can't spot what's wrong, although it's probably something simple.

Code:

Queue::Queue() {
	Front = Rear = 0;
}//end constructor

bool Queue::Empty() {
	return Front == Rear == 0;
}//end Empty

void Queue::Enqueue(int element) {
	if(Rear+1 == Front || (Rear+1 == maxqueue && !Front)) {
		cout << "Queue is full\n";
		return;
	}//if
	Rear++;
	if(Rear == maxqueue)
		Rear = 0; //circle
	Cue[Rear] = element;
}//end Enqueue

int Queue::Dequeue() {
	if (Front == Rear) {
		cout << "Queue is empty\n";
		return 0;
	}//if
	Front++;
	if (Front == maxqueue)
		Front = 0;
	return Cue[Front];
}//end Dequeue

There could also be a problem in this function, but I think it's ok.

Code:

void infix_to_postfix(string infix) {
       Stack stak;
	   Queue cue;
       for (int i=0; i<infix.size(); i++){
           
           if (infix[i] == '+' || infix[i] == '-' || infix[i] == '*' || infix[i] == '/' || infix[i] == '^' ){
               while (!stak.Empty() && order_ops(stak.Top()) <= order_ops(infix[i])){
                     cue.Enqueue(stak.Top());
                     stak.Pop();
               }//while
               stak.Push(infix[i]);
           }//if
           else if(infix[i] == '('){
                stak.Push(infix[i]);
           }//else if
           else if(infix[i] == ')'){
                while (stak.Top() != '('){
                      cue.Enqueue(stak.Top());
                      stak.Pop();
                }//while
                stak.Pop();
           }//else if
           else{
               cue.Enqueue(infix[i]);
           }//else
           
       } //for
       
       while (!stak.Empty()){
             cue.Enqueue(stak.Top());
             stak.Pop();
       }
       // Print queue (postfix) to screen
       if (!cue.Empty())
          cout << "Postfix : " << endl;
       while(!cue.Empty()){
            cout << cue.Dequeue();
            //cue.Dequeue();
       }//while
       cout << endl << endl;
}//end infix_to_postfix

Originally Posted by mikeman

I'm pretty sure the problem lies in my queue class, as what I'm getting is endless lines of "Queue is full". But I can't spot what's wrong, although it's probably something simple.

So what you should do is test your queue class separately. Alternatively, you turn your queue class into a wrapper for std::queue<int>, thus you can be pretty certain that if a bug is detected, then it lies with your infix to postfix conversion implementation, not with the queue implementation. Later, if necessary, you can always switch the implementation to your own queue implementation.

Code:

bool Queue::Empty() {
	return Front == Rear == 0;
}//end Empty

I don't think this is what you actually wanted to do. I'm guessing you're after something more like return Front==0 && Rear==0;
or return Front==Rear;


I would like to second what laserlight said about testing everything separately. You need to make sure that all of your pieces are working right before you try to put them together.

Got started on breaking it down but have to break till later, have a class to go to.

One issue I'm seeing and I think is due to type issues:
I load a char array with "ABCD" and load the first element into the stack and queue, and my output is "65" which would be ASCII Decimal code. Is this indeed caused by the fact that my return type is int while the loaded item, "A" in this instance, is a char? Or am I totally off base with this thought?

I need to output the actual character, as I'm going to have to evaluate the postfix when it's correctly translated, and well, ASCII does me no good! If this is what's going on, should I change my return types for things like push and pop / enqueue and dequeue to char instead of int or void?